Geophysical Evidence for Carbonate Platform Periphery Gravity Flows in the Xisha Islands,South China Sea  

作　　者：BAI Hongxin SUN Yue WANG Dawei WANG Weiwei WU Shiguo 

机构地区：[1]Institute of Deep-Sea Science and Engineering,Chinese Academy of Sciences,Sanya 572000,China [2]Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519000,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]College of Information and Control Engineering,China University of Petroleum,Qingdao 266580,China

出　　处：《Journal of Ocean University of China》2022年第4期837-848,共12页中国海洋大学学报（英文版）

基　　金：This work was supported by the Key Research and Development Program of Hainan Province(No.ZDYF2020209);the National Natural Science Foundation of China(No.42176083);the Key-Area Research and Deve-lopment Program of Guangdong Province(No.2020B1111020002).

摘　　要：High-resolution bathymetric and partial seismic data were utilized to determine the characteristics and distribution of mass-transport deposits(MTDs)in the Xisha area,North of the South China Sea.Many isolated carbonate platforms are found in this area,providing mass-wasting materials as a sediment source for MTDs.The MTDs in the study area were divided into three types(slide,slump,and debris flow)based on their rheological properties.The MTDs were mostly distributed at the toe of the carbonate platform slope,where a large amount of carbonate debris accumulated.A total of 32 MTDs were identified on the carbonate platform slopes.A systematic assessment of the MTD morphometric parameters showed that their total area covered 2225.2 km2,with the largest MTD covering 354.1 km2.These MTDs differ largely from the MTDs of other areas,especially in terms of sediment compositions and deposit processes.Gullies and channels on the slope and reefs on the top of the platform act as sediment conduits and carbonate-producing sources,respectively,playing vital roles in the distribution and generation of gravity flow deposits.The development model proposed in this work states that reefs disintegrate into carbonate debris and mix with seawater to form gravity flows,which scour the seafloor and accumulate at the downslope,eventually resulting in failure.Sediments from these failures turn into gravity flows,flowing into submarine canyons and channels.The results of this research further our understanding of the development pattern of MTDs in a carbonate setting.

关 键 词：mass-transport deposit geomorphology analysis multibeam bathymetry carbonate platform sediment conduit 

分 类 号：P736[天文地球—海洋地质] P631[天文地球—海洋科学]